Sealing arrangement for air heaters



May 11, 1965 w, H. RAYBURN 3,182,715

SEALING ARRANGEMENT FOR AIR NE TERs Filed Sept. 29, 1961 r 52 4 1 77 l HARM A I T .I: as o f i i 5f INVENTOR.

Wake/Al evyz/r/z BY United States Patent 3,182,715 SEALING AGEMENT FOR AIR I-EATERS "Walker H. Rayburn, Scio, N.Y., assignor, by mesne assiguments, to Combustion Engineering, Inc, a stock corporation of Delaware Filed Sept. 29, 1961, Ser. No. 141,714 Claims. (Cl. 1659) The present invention relates to rotary regenerative heat exchange apparatus and more specifically to an improved sealing arrangement adapted to preclude the bypassing of fluid between fixed and rotary parts thereof.

A rotary regenerative heat exchanger has a rotor including a cylindrical shell joined to a rotor post by radial partitions that form therewith compartments carrying heat absorbent material that is alternately contacted by heating gas and air or other fluid to be heated. The rotor is surrounded by a rotor housing having end or sector plates formed with openings to provide passage for the gas and air. To prevent intermixing of the two fluids the partitions forming the rotor compartments are usually provided with sealing means that wipe against the imperforate portions of the end plates.

The rotor and rotor housing in normal usage are both subject to extreme thermal and mechanical stresses that cause distortion of the rotor and adjacent end plates of sufficient magnitude to open a significant leakage path for fluid flow therebetween.

Efforts to preclude such relative distortion have evolved various arrangements, one of the more successful being an arrangement by which a radial sealing leaf is held in sealing relation with an adjacent end plate by a cantilever support that is not subject to the usual thermal deformation. The cantilever is supported solely at its radial inner end by the rotor post While its outer end extends radially outward toward the rotor shell to support the radial sealing means independent from the adjacent radial partition or rotor shell.

Since the radial partition and the cantilever support lie radially adjacent to one another, lateral distortion of the radial partition due to thermal or pressure differences may produce a frictional interference that prohibits the cantilever from acting independently whereby it is forced to distort along with the radial partitions. A similar situation obtains when slag deposits or other foreign products of combustion collect between the radial beam and the partition to create a frictional drag causing the radial beam to distort along with the radial partition. Thus the mere presence of a cantilever seal is not positive insurance that optimum sealing conditions will prevail.

This invention is directed to an arrangement for use with a cantilever seal of the accepted type that insures independent movement of the radial partition and of the cantilever support throughout a wide range of thermal distortion. The arrangement will be best understood upon consideration of the following detailed description of an illustrative embodiment thereof when read in conjunction with the accompanying drawings in which:

FIGURE 1 is an elevational view in section that shows a rotary regenerative heat exchanger embodying the invention.

FIGURE 2 is an enlarged fragmentary view of a portion of the sealing arrangement shown in FIGURE 1,

I and 3,182,715 Patented May 11, 1965 FIGURE 3 is a plan view of the cam actuating means as seen from 3-3 of FIGURE 2.

In the drawings the numeral 10 designates the cylindr-ical shell of a rotor divided into sector-shaped compartments by radial partitions 11 which connect it to a rotor post 12 that is in turn driven about its axis by a motor and reduction gearing 13. The rotor compartments each contain a mass of heat absorbent material usually in the form of closely spaced metallic plates which first absorb heat from hot gases or other heating fluid entering the heat exchanger through a duct 15 from a boiler or other source to be discharged after passing over the metallic plates through an outlet duct 16 to which aninduced draft fan (not illustrated) is usually connected. As the rotor is turned slowly about its axis the heated plates are moved into the stream of air admitted through the duct 17 After passing over the plates and absorbing heat therefrom the stream of air is directed to a boiler furnace or other place of use through an outlet duct 18. The rotor is surrounded by a housing 20 having apcrt-ured end plates 21 at opposite ends thereof that connect to the inlet and outlet ducts for the air and gas.

To preclude fluid bypassing the rotor through flow passage-ways created between distorted parts thereof, a series of radial seals 22 are supported on radially disposed cantilever beams 24 at one or both axially remote ends of the radial partitions. The beams 24 are supported only at their radial inner ends by a direct connec tion to the rotor post while their outboard ends slidably abut the edges of the radial partitions and are held adjacent thereto by a driving means 26 that traverses a slot in said beam and is connected to the radial partition. A circumferential seal 2-8 fitted to the end edge of the rotor shell 19 is adapted to contact or pass adjacent to the surface of a sealing ring 32 carried by the housing. Although the seal 28 is fixed to the housing the axial depth of sealing ring 32 permits considerable relative movement therebetween.

Usually a cantilever type arrangement as above de scribed will maintain a predetermined sealing relation with the adjacent end plate even though the radial partitions or other rotor structure distort extensively and move out of their normal arrangement. On occasion however, the radial beam and adjacent radial partition are subjected to operating conditions of lateral distortion or slagging that create sufficient interference to force the radial beam 24 to become locked to the adjacent radial partition and distort sufficient to open a pathway for the leakage of fluid therebetween.

In accordance with the invention therefore I provide an arrangement that intermittently imparts an axial force to the outboard end of the cantilever beams supporting the radial seal that actuates the beam toward its adjacent end plate independent from the radial partition. Intermediate periods of such beam actuation are periods during which special rapping or knocking means are adapted to apply a sharp blow to the rotor structure of effectively vibrate the independent parts including the radial beam and adjacent radial partition sufiicient to maintain complete separation and independence of action thereetween.

The seal actuating means comprises essentially a push rod 36 that extends radially through an opening 38 in the rotor shell 16 adjacent an end edge of the radial partition 11. Usually it is necessary to provide sealing means of 'the type herein defined only at the hot end of the rotor that lies adjacent the inlet for the heating fluid, although if conditions should warrant, the basic principle may be readily applied at the cold end of the rotor. Each push rod 36 is held in position by a cylindrical housing 40 that surrounds the opening 33 and includes a ported cap 42 that abuts a retraction collar 44 formed integrally with push rod 36 and is held against the inner surface of cap 42 by a compression spring 46. The outer end of push rod 36 terminates in plenum chamber 45 while its inner end extends through the rotor shell to a point adjacent lower arm 49 of the bell crank. The bell crank includes an upper arm 47 and is pivotally secured to the radial partition 11 by the connecting means 26 that slidably connects the radial beam to the radial partition. A buffer plate 48 on the radial beam 24 adjacent its outboard end provides means by which a radial force on the push rod 36 may be applied as an axial force to the radial beam when the push rod 36 is moved radially inward by actuating means on the rotor housing.

The actuating means for the push rod 36 includes a cam 52 in a sub-housing 54 carried on the periphery of the rotor housing. The cam is pivotally secured to the sub-housing 54 to permit its remote end to be moved radially by a screw adjustment means 56 into contact with the end of push rod 38. The cam 52 carries a guide 58 that insures a working relationship with the screw adjusting means 56 for any desired setting. The screw adjusting means is provided with a stop-collar 60 to limit movement of the cam and prevents imparting an excess actuation to the radial beam 24 when the lever arm 47 is moved against the buffer plate 48.

In operation the screw adjustment means for the cam is actuated to move the cam radially into contact with push rod 36 whereby rotation of the rotor will move the rod 36 radially against the lower arm 49 of the bell crank and force it to pivot. As the bell crank pivots, arm 47 is moved axially against buffer plate 4.8 to place an axial force on the radial beam on which it is mounted. When the push rod 36 is moved circumferentially past the cam 52, spring 46 expands suddenly to throw the push rod including the retraction collar 44 radially outward where the collar strikes the cap 42 and produces a rapping action upon the rotor shell and radial partitions that tends to maintain complete separation between the radial partition and adjacent cantilever beam.

By this arrangement each radial partition and adjacent radial beam is sequentially imparted an axial force and a rapping action. By varying the spacing of the cam actuators the frequency with which each beam is axially biased and rapped may be varied to provide any desired intensity of actuation activity.

After a rotor has been operating at elevated temperatures for a period of time the thermal distortion of the rotor and rotor housing becomes stabilized to the extent that no further actuation of the radial beam is required to maintain independence of action. At this time the screw adjusting means 56 may be withdrawn sufiicient to permit the cam 52 to lie out of contact with the ends of the push rods 38 until they are again required by conditions that promote rotor distortion.

While this invention has been described with reference to the ernbodimnet illustrated in the drawing, it is evident that various changes may be made without departing from the spirit of the invention, and it is intended that 'all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

I claim:

1. Heat exchange apparatus having a rotor adapted to rotate a mass of heat absorbent element alternately between a heating fluid and a fluid to be heated including a cylindrical rotor shell joined to a central rotor post by radial partitions to form sectorial compartments for said heat absorbent element, a rotor housing surrounding the rotor in spaced relation and having end plates at opposite ends thereof including apertures between imperforate portions that simultaneously direct a heating fluid and a fluid to be heated through spaced portions of the rotor, radial support arms positioned laterally adjacent the axially remote ends of each radial partition, said support arms having a dependent inner end secured to the rotor post and an independent outer end that terminates at a point adjacent the rotor shell, sealing means carried by said support arms adapted to bridge the space between the radial partitions and the imperforate portions of the end plates, and means actuated by rotation of the rotor about its axis intermittently applying an axial force against the ends of said radial arms to maintain them at all times independent and free from interference with the radial partitions.

2. Heat exchange apparatus as defined in claim 1 where the means for intermittently applying an axial force against the outer ends of said radial arms is actuated by the rotation of the rotor about its axis.

3. Heat exchange apparatus having a rotor adapted to rotate a mass of heat absorbent element alternately between a heating fluid and a fluid to be heated including a cylindrical rotor shell joined to a central rotor post by radial partitions that form sectorial compartments for said heat absorbent element, a rotor housing surrounding the rotor in spaced relation and having end plates at opposite ends thereof including apertures between imperforate portions that simultaneously direct a heating fluid and a fluid to be heated through spaced portions of the rotor, a radial support arm laterally adjacent at least one end of each radial partition afiixed to the rotor post and adapted to extend radially outward therefrom to a point spaced from the rotor shell, sealing means carried by said radial support arms adapted to bridge the space between the radial partitions and the imperforate portions of said end plates, and means on the rotor shell alternately rapping and biasing the radial support arm axially toward its adjacent end plate to maintain the radial support arms free from interference with adjacent radial partitions and in sealing relation with the adjacent end plate.

4. Heat exchange apparatus having a rotor adapted to rotate a mass of heat absorbent material alternately be tween a heating fluid and a fluid to be heated including a cylindrical rotor shell joined to a central rotor post by radial partitions to form sectorial compartments for the heat absorbent material, a rotor housing surrounding the rotor in spaced relation having end plates at opposite ends thereof including apertures between imperforate portions that simultaneously direct a heating fluid and a fluid to be heated through spaced portions of the rotor, a radial support beam laterally adjacent an end of each radial partition aflixed to the rotor post and extending outward therefrom to a point spaced from the rotor shell, sealing means carried by said support beams adapted to bridge the space between the radial partitions and the imperforate portions of said end plates, and means on the rotor shell alternately rapping and biasing the radial support beams toward the adjacent end plate comprising a push rod extending radially through an opening adjacent each radial beam, means for transposing radial movement of said push rod into an aixal force against the radial beam, and actuating means carried by the rotor housing adapted to intermittently move each push rod radially inward in response to movement of the rotor about its axis.

5. Heat exchange apparatus having a rotor adapted to rotate a mass of heat absorbent element alternately between a heating fluid and a fluid to be heated including a cylindrical rotor shell joined to a central rotor post by radial partitions to form sectional compartments for said heat absorbent element, a rotor housing surrounding the rotor in spaced relation thereto having end plates at opposite ends including apertures between imperforate portions that simultaneously direct a heating fluid and a fluid to be heated through spaced portions of the rotor, radial support arms positioned laterally adjacent axially opposite ends of each radial partition, said support arms having their inner ends secured to the rotor post and their outer ends lying in spaced relation with the rotor shell, sealing means carried by said support arms extending axially thereof to bridge the space between the radial partitions and the irnperforate portions of the end plates, an actuating rod extending radially through the rotor shell adjacent each sealing means, means applying a radial force against said rod, and means transposing said radial force into an axial force against the outer end of said radial support arm whereby the radial seal is maintained in sealing relation with the adjacent end plate.

References Cited by the Examiner UNITED STATES PATENTS 2,122,176 6/38 Herbeck et al 1655 2,372,997 4/ 45 Yerrick et al l655 2,874,939 2/59 Rahr et al 1659 2,936,160 5/60 Nilsson et a1. s 165--8 CHARLES SUKALO, Primary Examiner. HERBERT L. MARTIN, Examiner. 

1. HEAT EXCHANGE APPARATUS HAVING A ROTOR ADAPTED TO ROTATE A MASS OF HEAT ABSORBENT ELEMENT ALTERNATELY BETWEEN A HEATING FLUID AND A FLUID TO BE HEATED INCLUDING A CYLINDRICAL ROTOR SHELL JOINED TO A CENTRAL ROTOR POST BY RADIAL PARTITIONS TO FORM SECTORIAL COMPARTMENTS FOR SAID HEAT ABSORBENT ELEMENT, A ROTOR HOUSING SURROUNDING THE ROTOR IN SPACED RELATION AND HAVING END PLATES AT OPPOSITE ENDS THEREOF INCLUDING APERTURES BETWEEN IMPERFORATE PORTIONS THAT SIMULTANEOUSLY DIRECT A HEATING FLUID AND A FLUID TO BE HEATED THROUGH SPACED PORTIONS OF THE ROTOR, RADIAL SUPPORT ARMS POSITIONED LATERALLY ADJACENT THE AXIALLY REMOTE ENDS OF EACH RADIAL PARTITION,SAID SUPPORT ARMS HAVING A DEPENDENT INNER END SECURED TO THE ROTOR POST AND AN INDEPENDENT OUTER END THAT TERMINATES AT A POINT ADJACENT THE ROTOR SHELL, SEALING MEANS CARRIED BY THE SUPPORT ARMS ADAPTED TO BRIDGE THE SPACE BETWEEN THE RADIAL PARTITIONS AND THE IMPERFORATE PORTIONS OF THE END PLATES, AND MEANS ACTUATED BY ROTATION OF THE ROTOR ABOUT ITS AXIS INTERMITTENTLY APPLYING AN AXIAL FORCE AGAINST THE ENDS OF SAID RADIAL ARMS TO MAINTAIN THEM AT ALL TIMES INDEPENDENT AND FREE FROM INTERFERENCE WITH THE RADIAL PARTITIONS. 